Macro-meso-microscopic Multi-scale Mechanism Of Hydration Instability Of Mudstone Anchorage Structure

For argillaceous soft rock roadway,water is an important factor affecting its safety and stability,and if effective support and control measures are not taken,it will lead to the overall destabilization of the roadway surrounding rock anchorage structure and thus induce engineering disasters.At present,there are still many roofing accidents caused by groundwater erosion of the surrounding rock anchorage structure in China,which greatly affects the safety production of coal mines,and it is crucial to obtain the bearing mechanism of anchorage structure for soft rock under the action of water.Based on this,the thesis conducted a macro-meso-micro-scale experimental study on the bearing characteristics of anchorage structure for soft rock under different water content and stress levels,revealed the mechanism of weakening and destabilization of anchorage structure for soft rock under the action of hydration damage,and proposed safety control countermeasures for muddied roadway surrounding rocks.The innovative results are as follows.(1)Taking anchorge unit for soft rock,the basic component unit of argillaceous soft rock roadway anchorage structure,as the research object,we conducted loading tests on anchorge unit for soft rock under different moisture content and stress levels,and adopted a loading path that conforms to the actual stress state of the anchorage structure to obtain the deformation and damage characteristics of anchorge unit for soft rock,acoustic emission characteristics and anchor axial force distribution law corresponding to moisture content and stress level,and revealed the The evolution characteristics of the bearing performance of anchorge unit for soft rock under the action of hydration damage and the synergistic mechanism among the components were revealed.(2)By separating the rock-anchor structure from the anchor solid with the results of anchorge unit for soft rock mechanical tests,rock-anchor structure direct shear tests and interface splitting tests were conducted at different moisture contents,and the rockanchor structure direct shear strength,damage mode,acoustic emission characteristics and interface adhesion properties evolved with moisture content were obtained,which clarified the weakening mechanism and failure mode of rock-anchor structure from the macroscopic level.(3)Based on the results of macroscopic mechanical tests,we obtained the mesoparameters of anchorage structure under different moisture contents,and used the coupled PFC-FLAC model to construct the structural models of anchorage monomer and rock-anchor agent under different moisture contents,to simulate the anchor solid loading process and rock-anchor agent direct shear process,to obtain the particle transport,microfracture development and agglomeration,energy evolution and stress distribution laws during the deformation and damage of specimens,to analyze the effect of water on the inter-particle adhesion stress state,and to investigate the mechanism of water on the weakening of the bearing performance of anchorage structure for mudstone at the mesoscopic level.(4)The SEM and nanoindentation tests of rock-anchor structure were carried out to analyze the deformation characteristics and mechanical strength of rock and interface under water erosion,and to reveal the weakening failure mechanism of rock-anchor structure under the effect of hydration damage from the microscopic level.(5)Based on the hydration damage test of anchorage structure for mudstone under different scales,we clarified the mechanism of macro-meso-microscopic action of weakening and destabilization of anchorage structure for mudstone under the action of hydration damage,and proposed the safety control measures for anchorage structure of seepage mud roadway surrounding rock,and successfully applied to field engineering practice.There are 111 figures,21 tables and 180 references in this thesis.